Piston



m, mm. WWW

- J. WATSON PISTON Filed Jan. 9, 192a INVETUR Patented Nov. Id, Wm.

JAMES WATSON, 01E" TORONTO, ONTARIO, CANADA, ASSIGNOR 0F ONE-HALF TO EDWARD JONES, 01E MOUNT DENNIS, ONTARIO, CANADA.

PISTON.

application filed January 9, 1922. Serial No. 528,088.

To all whom it may concern:

Be it known that I, JAMES WATSON, of the city of Toronto, in the county of York, Province of Ontario, Canada, a subject of the King of Great Britain, have invented certain new and useful Improvements in Pistons, of which the following is a specification.

This invention relates to improvements in pistons particularly adapted for internal combustion engines, and the chief object of my invention is to devise a piston of this type which will automatically take care of any wear in the cylinder.

ith pistons in which the wrist pin or other support is connected with the sides of the iston there is a marked tendency under tlie force of the explosion for the piston to expand so that its sides grip the wall of the cylinder, and it is therefore a further object of my invention to devise'an improved connection between the piston and its connectingrod, which connection will be with only the head of the piston, so that the sides of the piston will be entirely unadected by the force of explosion.

I attain my object by means of the con-- structions hereinafter described and illustrated in the accompanying drawings in which Fig. 1 is a vertical section through my improved piston;

Fig. 2 a side elevation of the same; and

Fig. 3 a plan view of the piston looking at the under side.

In the drawings like numerals of reference indicate corresponding parts in the difi'erent figures.

The piston as usual comprises the head 1 and sklrt 2 into al therewith. The skirt 2 will preferably ave a portion 2 of greater thickness adjacent the head, in which will be formed the usual ooves 3 for the piston rings. The head of t e piston will, of course, be ground slightly undersize, while its skirt will be tapered so that its lower end will be somewhat over size, for the cylinder for which it is intended, say substantially three one-thousands of an inch, although in the drawings the amount of taper is greatly exaggerated.

The skirt of the piston is slit diagonally from its lower edge to a point just below the thickened portion 2, which slit will be formed before the cylinder is ground in.

order that the lower end of the piston will be perfectly circular after grinding.

This slit 4 permits the contraction of the lower end of the piston to enable the piston to be placed within the cylinder. One slit will usually be suflicient'. but more may be formed if found desirable.

The lower end 2*" of the skirt of the piston will preferably be of slightly greater thickness for the purpose of stiifenin the skirt.

From the construction descri d it will be seen that the lower end of the skirt of the piston acts as a piston ring, and that as the skirt of the piston wears, the piston gradually works back to its normal shape, so that the skirt of the piston always tightly fits the cylinder.

Pistons as ordinarily constructed have a tendency to rock under the force of the explosion and thus wear the sides of the cylinder at the upper end. The forming of the lower end of the skirt of the iston oversize pratically prevents this rocking movement and therefore lessens the wear on the cylinder.

For connecting the piston to the connecting rod, I form integral with the head of the piston the ribs 5, the lower ends of which support a socket 6 to receive the end of the connecting rod, which is formed an a ball 7 The ball 7 is held in position by means of a cap 8, formed in two halves,

which is secured to the socket 6 by means of bolts 9. Dowel pins 10 are provided on one half of the cap 8 adapted to enter holes in the other half of the cap for the purpose of properly positioning the same. In the socket 6 between the ribs 5 are formed oil holes 11 for lubricating purposes.

Shims 14 are provided between the socket 6 and cap 8, and these shims may be removed to take up wear as necessary.

In order to prevent the nuts on the bolts 9 working loose, a hole 12 is drilled through each bolt above the nut and a wire 13 is passed through the holes.

From the construction described It Wlll be seen that I have devised a construction of piston which will satisfactorily attain the objects of my invention as set forth in the preamble of this specification. It will be noted that there is absolutely no connection between the wall or skirt of the piston and the ball socket connection between the piston and the connecting rod.

IOU

What I claim as my invention is 1. A trunk piston comprising a head; a resilient skirt, substantially circular in all its external cross sectional contours, depending therefrom and having a single diagonal slit therein extending from the lower edge of the skirt to a point substantially diametrically opposite and close to the head, said slit portion gradually increasing in diameter from its upper to its lower end, said lower end normally being of greater diameter than the cylinder for which it is intended; and a bearing for a'connecting rod connected only with the head of the piston whereby the skirt is free to expand and contract.

2. A trunk piston comprising a head; a resilient skirt, substantially circular in all its external cross sectional contours, depending therefrom and having a single diagonal slit therein extending from the lower edge of the skirt to a point substantially diametrically opposite and close to the head, said slit portion gradually increasing in diameter from its upper to its lower end, said lower end normally being of greater diameter than the cylinder for which it is intended, and a bearing for a connecting rod, connected only with the head of the piston whereby the skirt is free to expand and contract, the inside of the skirt havin a rib formed thereon ad'acent its lower e ge.

Signed at Toronto, am, this 29th day of December, 1921.

JAMES WATSON. 

